Scientific name: Favonius quercus

Underwings grey with white streak and small tails, upper wings brown. Males have a purple sheen, females have a purple mark on forewing.

This handsome butterfly is widely distributed throughout southern areas wherever there are oak trees; even a solitary tree may support a colony. It is frequently overlooked as adults remain largely in the canopy where the main adult food source is honeydew; they fly more commonly in the evening of a warm summer's day. They are only driven down to seek fluid and nectar during prolonged drought, as occurred in 1995-6.

There has been a recent increase in records and an extension of the range of this butterfly especially in the English Midlands and south-west Scotland, even in urban areas (including London) which may be related to improvements in atmospheric quality. White-letter Hairstreak is similar but has W-shaped streak.

Size and Family

Family: Hairstreaks

Size: Small

Wing Span Range (male to female): 37-39mm

Distribution

Countries: England, Wales, Ireland and Scotland

Widespread in England and Wales, less common in Scotland and Ireland

Distribution Trend Since 1970’s in Britain: -15%

Conservation Status

Butterfly Conservation priority: Low

Fully Protected under the 1985 Northern Ireland Wildlife Order

European status: Not threatened

Caterpillar Foodplants

The Purple Hairstreak is restricted to Oak trees including both the native species, Sessile Oak (Quercus petraea) and Pedunculate Oak (Q. robur), and the introduced Turkey Oak (Q. cerris). Evergreen Oak (Q.ilex) also may be used.

Habitat

Difficult to spot as it flies around the tops of Oak trees in woods, hedgerows and parks, including in urban areas.